*{
    padding: 0;
    margin: 0;
    box-sizing: border-box;
}
.container{
    width: 1130px;
    margin: auto;
}
nav{
    background-color: #000;
}
nav ul::after{
    content: "";
    display: block;
    clear: both;
}
nav li{
    float: left;
    list-style: none;
}
nav a{
    color: white;
    text-decoration: none;
    font-size: 14px;
    padding: 24px 20px;
    display: block;
}
nav a:hover{
    background-color: #fff;
    color: black;
}
nav .active a{
    background-color: #fff;
    color: black;
}
.banner{
    background-color: #2ba3d4;
    text-align: center;
    padding-top:130px;
    padding-bottom: 130px;
    color: #fff;
}
.banner img{
    margin-bottom:30px;
}
.banner p{
    margin-bottom:30px;
}
.banner a{
    color: #2ba3d4;
    padding: 18px 28px;
    background: #fff;
    display: inline-block;
    text-decoration: none;
    border-radius: 3px;
    border: 1px solid white;
}
.banner a:hover{
    background: #2ba3d4;
    color: white;
}
.become{
    padding-top: 150px;
    padding-bottom:150px;
    text-align: center;
}
.become h2{
    font-size: 36px;
    margin-bottom:50px;
    font-weight:200;
}
.row{
    margin-left:-15px;
    margin-right:-15px;
}
.col-4{
    width: 33.333333%;
    float: left;
    padding: 15px;
}
.item{
    border: 1px solid #e5e5e5;
    border-bottom-color: #0ba1d8;
    padding: 30px;
    padding-bottom: 60px;
}
.become .col-4 h3{
    margin-top: 26px;
    margin-bottom: 22px;
}
footer{
    margin-top: 273px;
    background-color: #252525;
    padding-top: 110px;
    padding-bottom: 110px;
}
footer p{
    color: #dddddd;
    text-align: center;
}
/*响应式代码*/
@media (max-width: 600px) {
    .container{
        width: 100%;
    }
    .col-4 ,.col-3{
        width: 100%;
    }
    footer{
        margin-top: 970px;
    }
    .row{
        margin-left: 0;
        margin-right: 0;
    }
    .become{
        padding-top: 72px;
    }














}
